Huddled around an electric heater with his wife and baby daughter, Krasimir Ivanov admitted he never thought much about politics. "But that was before it entered my own living room." He checks the radiator for signs of life. To no avail. The tiny 7th floor two-room flat remains as frigid as it has been since the central heating suddenly went cold on Wednesday, shortly after gas supplies from Ukraine were shut off. With temperatures outside plummeting to -16C, and thousands of apartments heat-less, the Ivanovs have spent the past few days trying to keep their daughter Anjela warm.

"Medical advice is to keep the temperature at 20 degrees," said Krasimir. "We can barely afford the electricity bill we'll receive at the end of this. But it's simple - if we don't pay for electricity, we'll be paying for medicine for our child."

And yet the flat is warm compared to Pavlina's place of work at a TV ratings company in central Sofia, where there is no heating at all and staff keep their coats on at their computers. "The bosses have resisted our pleas for electric heaters so we just sit there and freeze all day, hardly able to concentrate," she says. "At the end of the day I hurry home through the ice and snow to try and warm up."

Things will get even more complex if Anjela's nursery is shut down, a very real prospect if relief does not come soon. "Anjela might have to go to my mother-in-law near Kazanluk, in central Bulgaria who heats with a wood-burning stove. It's bizarre, isn't it, that in 2009 she's actually better off with such primitive heating?"

"We feel like pawns in someone else's game," said Krasimir with a philosophical grin.

That game of diplomatic chess mixed with energy hardball appeared to be inching closer to resolution yesterday, but even if the gas taps are switched back on, Bulgarians are still facing a chilly weekend. The earliest that supplies can be restored is Monday.

In the meantime, the country is left to rue its position as the most vulnerable EU state to the habitual rows between Russia and Ukraine over gas supplies and payments. Bulgaria sources almost all of its gas from Russia. When it is turned off, the country feels its acutely. Schools were closed as pupils were sent home. Concern even spread to the prisons and their inmates, who "unlike pupils can't be sent home," said justice minister Meglena Tacheva. Taxis which run on methane gas, were largely off the roads. Drivers of trams were ordered to turn off heating on public transport between 10 am and 4pm, although there was much evidence the order was being defied.

"I don't think they'd dare," said pensioner Davinka Ivanova, 62, dressed against the cold in leather trousers and a fur coat, on the number 1 tram in central Sofia. "There'd be a revolt. It's cold enough outside and in our homes as it is."

Gas supplies to many companies, except for those production plants who could not do without it, was cut back. Glass, steel, beer and metal producers were forced to shut down, as experts estimated the loss to industry to be around 500m Bulgarian Lev (£227m) a day.

Electric heaters were brought into Sofia zoo to ensure the survival of its animals, particularly the elephants, monkeys, reptiles and fish. The consumption of electricity soared to record levels as people sought alternative forms of heating. Lighting on public buildings and Christmas illuminations were turned off.

"We've sold 240 electrical heaters in two days," said Alexandra Nikolova, sales assistant in an electrical shop.

The air was thick with a mix of tar and burning rubber, as some plants switched from gas to heating oil. The anger was palpable. "Who will pay for this?" asked Irina Bankova who runs a small bakery production line in eastern Sofia which has seen a slump in trade this week as businesses she provides with breads and cakes have been temporarily forced to close. "I don't expect we'll see any compensation from those responsible." If it continued she said, she would be forced to lay some of her work force off.

Other criticism trained on the government for doing next to nothing to diversify Bulgaria's energy supply.

"Bulgaria is almost 100% dependent on Russia for energy, and has no access to any alternative gas routes or suppliers," said Ognyan Minchev, a political analyst with the independent thinktank the Institute of Regional and International Studies. "In the 20 years since the end of communism, the Bulgarian government has done almost nothing to change this state of affairs, indeed it has only deepened Bulgaria's dependence on Russia," he said, highlighting a controversial gas contract signed between Russia and Bulgaria two years ago.

"Being dependent on the goodwill of Gazprom in a harsh winter leaves Bulgaria not just vulnerable, but helpless, and it amounts to a complete negligence and betrayal of national interests," he added.

To the alarm of the European Union, President Georgi Parvanov's populist reaction to the crisis has been to suggest firing up a mothballed reactor at the Kozloduy nuclear plant which was shut down amid safety concerns as a condition of Bulgaria's accession to the EU in 2007. The proposal has received much support at home.